Spark plug



Aug 25, 1935- w. K. ANpERsEN v 2,052,335

SPARK PLUG Filgd uFeb. 1o, 193e ATTORNEYS l Patented. Aug. `25, 1936 UNITED STATES 'PA/TENroFl-lce SPARK PLUG William K. Andersen, Brooklyn, N. Y. Application February 1o, 193e, serial No. 63,654

f 'z claims. (ci. 12s-169) This invention relates to an improvement in spark plugs for internal combustion engines and more particularly to a means incorporated in thev spark plugfor providing a supplemental spark intensiiler between the center electrode and terminal screw when the plug is in a cold condition, and which means automatically closes the gap and eliminates the spark when the means is heat-` ed by the oxplosion of the gases within the engine cylinder. y One object of the invention is to provide a spark plug having enclosed therein a thermostatic element connected with the center electrode and normally spaced from the terminal screw l5 connection to form a relatively small spark gap which is closed when the element is heated, thereby intensifying the initial eiect of the electrical current and increasing the action of the spark delivered at the 'xed or permanent spark gap in the usual manner.

Another object is to provide certain improvements in the form, construction, and arrangement of the parts, whereby the above named and other objects mayeiectively be attained.

A practical embodiment of my invention is represented in the accompanying drawing, in which Fig. 1 represents a vertical central section of a spark plughaving my improvements incorporated therein; 30 Fig. 2 represents a Similar view ofthe upper portion of the spark plug with the parts in' another position; and Fig. 3 represents a horizontal Section taken in i the plane of the line III-III of Fig. l, looking in the direction of the arrows.

The body, of the Spark plug is of conventional form and denoted by I, the interior bores by 2,

. 3, the insulator by 4, the clamp nut by 5, which is Screw threaded in the threaded bore 6 of the body 40 and secures the insulator in position in the bores 2,43 of the body. Thebody I is eXterlorly screw f threaded atfl for aiiixing it to the cylinder of theA internal combustion engine (not shown) inthe -y A well known manner. A iixed electrode 8 extends 45 from the lower end of the body and-is disposed to coact with the centenelectrodel 9 secured inthe insulator 4, between which electrodes and 9 the permanent and comparatively wide spark gap'is formed. This center electrode@ is xed 50 in the insulator by means of a bushing lll which I2, together withthe electrode 9 are permanently xed in the insulator by means of cement. or

other suitable means. The upper end of the insulator 4 is formed with a screw threaded bore I3 arranged to receive the screw threaded por- 5 tion I4 of the terminal connector I5. This connector I5 is provided with a screw threaded shank I6 and nut Il for the reception of the distributor y 'I'he connector also has ya concentric chamber I8 in open communication 10 with the bore I3 .of the insulator Ilv and radial openings I9 leading from the chamber I8 'to the outside, so that air may be freely admitted to and from the chamber' to serve as a peep sight as well 1 as cool the plug.

A thermostatic element comprising, in the present instance, a pair of fingers 20, 2i disposed in intimate contact with each other and having their lower ends permanently iixed in a 'recess 22 in the upper end of the bushing I il and in longitudinal allnement with theelectrode Q. The fingers 20, 2l extend upwardly from the bushing Ill through the bore I3 into the chamber It of the connector` i5, and the upper ends thereof are bent outwardly away from each other, as shown at 23, 24, respectively. The bent upper ends 23, 24 of the fingers are disposed above the radial openings l'in position to be normally spaced a relatively small distance away from the interior wall of the chamber IB, thereby forming narrow spark intensifying gaps 25, 26. Each of the fingersv 20, 2l Ais composed of two metallic plates having different coefilcients of expansion when subjected to heat, such as brass and nickel, steelyor the like.- The plates in each of the iingers are permanently and xedly united throughout their entire .contacting surfaces and are so arranged that the adjacent surfaces of *he iingers, when assembled in the plug, will be of the similar material, such as brass to brass, etc. 1

Thus, it will be seen that when the spark plug is cold,'the parts will assume the position shown in Figs. l and 3,v in which position Ythe .lingers 2li, il of the thermostatic element will bein intimate contact with each other throughout their length, 45 while the upper bent ends 23, 2d will be spaced from the walls of the chamber Ih Whenanelectrical impulse is passed through the distributor Wire (not shown) to the connector I5 through the shank I@ and nut Il, the current will jump V0 across the gaps it, 26V between ends 23, 2li of the iingers tu, il and the wall of the chamberlt, after which it willpass downwardly through the lingers and bushing It to the electrode t whence it will again cross to the fixed electrode t and liti" ignite the gases in the cylinder of the engine (not shown). By igniting the gases in, the cylinder the spark plug as a whole will become heated,'

which heat being carried through the electrode 9, bushing I and fingers 20, 2| will cause the brass surfaces of the fingers to expand and flex the fingers above the bushing I0 so that they will move in opposite directions away from each other at the upper ends. 'Ihis outward movement of the fingers 20, 2| will bring the bent ends 23, 24 respectively, into contact with the wall of the chamber 8 and thereby close the gaps so that the electrical impulse will be passed directly through the connector l5, fingers 20, 2|, bushing |0, and electrode 9 where the firing spark will be formed with the fixed electrode 8 in the usual manner. When the electrical impulses which form the spark cease, and the spark plug, together with its associated parts have become cool, the fingers will re-iiex and return to their normal position, so that the bent ends 23, 24` of the fingers will be spaced from the wall of the chamber I8 and set ready to receive the initial electrical impulse for starting the engine. From the foregoing it will be seen that I have devised a spark plug having an automatically operated thermostatic element forming a part of and incorporated within the spark plug structure, which element tends to produce an intense initial spark ory sparks between the fingers and the terminal screw, and from which the electrical energy is carried to the center electrode to bridge the fixed gap where a firing spark ignites the gases in the cylinder more readily so that the engine is started much easier when cold.

It will be understood thatvarious changes may be resorted to in the form, construction and arrangement of the several parts without departing from the spirit and scope of my invention, and hence I do not intend to be limited to the details herein shown and described except as they may be included in the claims.

What I claim is:

1. A spark plug having in combination with its permanent spark gap a supplemental spark intensifying gap. and a thermostatically operated element arranged to close said supplemental gap when'the plug is heated.

2. A spark plug having in combination with its fixed and center electrodes forming its pennanent r, spark gap, a terminal connector, a thermostatically operated element connected with the center electrode and arranged to form a supplemental spark intensifying 4gap between it and said terminal connector when the plug is cold and actuated to close said supplemental gap when heated.

3. A spark plug comprising a body having a. fixed electrode, an insulator carried by said body and provided with a center electrode, a terminal connector secured to said insulator and spaced from said center electrode, and a thermostatically operated element connected to the center electrode and extending upwardly therefrom in position to contact with said terminal connector when heated and break contact therewith to form a supplemental spark intensifying gap ther between when cold.

4. A spark plug comprising a body having a fixed electrode, an insulator carried by said body and having a hollow outer end, a center electrode secured in theinner end of said insulator and arranged to coact with said fixed electrode to form a permanent spark gap, a terminal connector secured to theouter hollow end of said insulator and spaced from said center electrode, and a thermostatically operated element connected to the center electrode and extending upwardly therefrom into the hollow end of the insulator in position to be brought into contact with said terminal connector when heated and break contact therewith to form a supplemental spark intensifying gap therebetween when cold.

5. A spark plug comprising a body having a xed electrode, an insulator carried by said body and having a hollow outer end, a center electrode secured in the inner end of said insulator and arranged to coact with said fixed electrode to form a permanent spark gap, a terminal connector secured to the outer hollow end oi said insulator and spaced from said center electrode, said terminal connector having a chamber therein, and a thermostatically operated element connected to the center electrode and extending upwardly therefrom into said chamber in the ter- /minal connector in position to be brought into Vcontact with the walls of the chamber when heated and break contact therewith to form a supplemental spark intensifying gap therebetween when cold. v

6, A spark plug comprising a body having a fixed electrode, an insulator carried by said body and having a'hollow outer end, a center electrode secured in the inner end of said insulator and arranged to coact withv said fixed electrode to form a permanent spark gap, a terminal connector secured to the outer hollow end of said insulator and spaced from said center electrode, said terf minal connector having a chamber therein, and

a thermostatically operated element comprising at least two members connected at their lower ends to the center electrode and extending upwardly therefrom into said chamber in the terminal connector, the free ends of said element being disposed to be moved in opposite directions toward and away from each other so as to be brought into contact with the walls of the chamber when heated and breakcontact therewith to form a supplemental spark intensifying gap therebetween when cold.

7. A spark plug comprising a body having a fixed electrode, an insulator carried by said body and having 'a hollow outer end, a center electrode secured in the inner end of said insulator and arranged to coact with said fixed electrode to form a permanent spark gap, a terminal connector secured to the outer hollow end of said insulator and spaced from said center electrode, said terminal connector having a chamber therein, and a thermostatically operated element comprising at least two members connected at their lower ends to the center electrode and extending upwardly therefrom into said chamber in the terminal connector, the free ends of said element being bent outwardly and disposed to be moved in opposite directions toward and away from each other so that the bent ends will be brought into contact with the walls of the chamber when heated and break contact therewith to form a supplemental spark intensifying gap therebetween when cold.

WILLIAM K. ANDERSEN. 

